This is a question I get asked a lot by those starting to learn to draw. Holding a pencil for drawing is similar in a way to holding a pen for handwriting in that there are ways that get better results, however it is a personal choice. Just like handwriting we all have a unique style so I think the best advice is however it feels best.
I believe and I am sure most art teachers will tell you that drawing from life is always better than drawing and painting from photographs. I think particularly if you are learning to draw then drawing from life is essential.
Of course there is nothing wrong with drawing and painting from photographs and while working on illustration commissions I have in the past used many references from photographs an images. Sometimes it isn’t possible to observe the subject in life.